ios - 圆形动画不起作用

Question

我正在 View 中绘制一个加载圆。如果我直接使用“初始 View Controller ”打开 View 。圆圈正在动画，但如果我选择从以前的 View (桌面 View )打开它。它带有绘图功能，但没有动画。我试图在viewdidload中调用setup()、didawake函数，但仍然没有机会。它不起作用。

class SpinningView: UIView {

    let circleLayer = CAShapeLayer()

    override init(frame: CGRect) {
        super.init(frame: frame)
        setup()
    }

    required init(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)!
    }

    override func awakeFromNib() {
        super.awakeFromNib()
        setup()
    }
    @IBInspectable var lineWidth: CGFloat = 4 {
        didSet {
            circleLayer.lineWidth = lineWidth
            setNeedsLayout()
        }
    }

    func setup() {
        circleLayer.lineWidth = lineWidth
        circleLayer.lineWidth = 10
        circleLayer.fillColor = nil
        circleLayer.strokeColor = UIColor(red: 0.8078, green: 0.2549, blue: 0.2392, alpha: 1.0).cgColor
        layer.addSublayer(circleLayer)
        tintColorDidChange()
        updateAnimation()
    }
    func updateAnimation() {
        if animating {
            circleLayer.add(strokeEndAnimation, forKey: "strokeEnd")
            circleLayer.add(strokeStartAnimation, forKey: "strokeStart")
        }
        else {
            circleLayer.removeAnimation(forKey: "strokeEnd")
            circleLayer.removeAnimation(forKey: "strokeStart")
        }
    }
    override func layoutSubviews() {
        super.layoutSubviews()

        let center = CGPoint(x: bounds.midX, y: bounds.midY)
        let radius = min(bounds.width, bounds.height) / 2 - circleLayer.lineWidth/2

        let startAngle = CGFloat(-M_PI_2)
        let endAngle = startAngle + CGFloat(M_PI * 2)
        let path = UIBezierPath(arcCenter: CGPoint.zero, radius: radius, startAngle: startAngle, endAngle: endAngle, clockwise: true)

        circleLayer.position = center
        circleLayer.path = path.cgPath
    }
    override func prepareForInterfaceBuilder() {
        super.prepareForInterfaceBuilder()
        setup()
    }
    override func tintColorDidChange() {
        super.tintColorDidChange()
        circleLayer.strokeColor = tintColor.cgColor
    }
    @IBInspectable var animating: Bool = true {
        didSet {
            updateAnimation()
        }
    }

    let strokeEndAnimation: CAAnimation = {
        let animation = CABasicAnimation(keyPath: "strokeEnd")
        animation.fromValue = 0
        animation.toValue = 1
        animation.duration = 2
        animation.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseInEaseOut)

        let group = CAAnimationGroup()
        group.duration = 2.5
        group.repeatCount = MAXFLOAT
        group.animations = [animation]

        return group
    }()

    let strokeStartAnimation: CAAnimation = {
        let animation = CABasicAnimation(keyPath: "strokeStart")
        animation.beginTime = 0.5
        animation.fromValue = 0
        animation.toValue = 1
        animation.duration = 2
        animation.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseInEaseOut)

        let group = CAAnimationGroup()
        group.duration = 2.5
        group.repeatCount = MAXFLOAT
        group.animations = [animation]

        return group
    }()


}

Answer 1

我通过在 viewdidappear 中调用 awakefromNib() 函数解决了这个问题。所以我的代码创建了一个像谷歌圆圈一样动画的圆圈。

override func viewDidAppear(_ animated: Bool) {
    mSpinningView.awakeFromNib()
}